Background: Extensive surgery on advanced-stage epithelial ovarian cancer is associated with increased postoperative morbidity, which may cause a delay in or omission of chemotherapy. We examined postoperative complications and their effects on adjuvant treatment in patients undergoing primary debulking surgery (PDS). Methods: Stage IIIC-IV epithelial ovarian cancer patients who underwent PDS between January 2013 and December 2020 were included. Patients were divided into two groups according to the radicality of the operation, i.e., extensive or standard surgery, and their outcomes were compared. Results: In total, 172 patients were included; 119 underwent extensive surgery, and 53 had standard surgery. Clavien–Dindo grade 3–5 (CDC 3+) complications were detected in 41.2% of patients after extensive operations and in 17% after standard surgery (p = 0.002). The most common CDC 3+ complication was pleural effusion. Despite the difference in the complication rates, the delay in chemotherapy did not differ between the extensive and standard groups (p = 0.98). Conclusions: Complications are common after PDS. Extensive surgery increases the complication rate, but most complications can be treated effectively; therefore, a delay in adjuvant treatment is rare.